net/sched/act_pedit.c

   1 /*
   2  * net/sched/act_pedit.c        Generic packet editor
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Jamal Hadi Salim (2002-4)
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/errno.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <linux/tc_act/tc_pedit.h>
  24 #include <net/tc_act/tc_pedit.h>
  25 #include <uapi/linux/tc_act/tc_pedit.h>
  26 #include <net/pkt_cls.h>
  27
  28 static unsigned int pedit_net_id;
  29 static struct tc_action_ops act_pedit_ops;
  30
  31 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  32         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  33         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  34 };
  35
  36 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  37         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  38         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  39 };
  40
  41 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  42                                                         u8 n)
  43 {
  44         struct tcf_pedit_key_ex *keys_ex;
  45         struct tcf_pedit_key_ex *k;
  46         const struct nlattr *ka;
  47         int err = -EINVAL;
  48         int rem;
  49
  50         if (!nla || !n)
  51                 return NULL;
  52
  53         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  54         if (!keys_ex)
  55                 return ERR_PTR(-ENOMEM);
  56
  57         k = keys_ex;
  58
  59         nla_for_each_nested(ka, nla, rem) {
  60                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  61
  62                 if (!n) {
  63                         err = -EINVAL;
  64                         goto err_out;
  65                 }
  66                 n--;
  67
  68                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  69                         err = -EINVAL;
  70                         goto err_out;
  71                 }
  72
  73                 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
  74                                                   ka, pedit_key_ex_policy,
  75                                                   NULL);
  76                 if (err)
  77                         goto err_out;
  78
  79                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  80                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  81                         err = -EINVAL;
  82                         goto err_out;
  83                 }
  84
  85                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  86                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  87
  88                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  89                     k->cmd > TCA_PEDIT_CMD_MAX) {
  90                         err = -EINVAL;
  91                         goto err_out;
  92                 }
  93
  94                 k++;
  95         }
  96
  97         if (n) {
  98                 err = -EINVAL;
  99                 goto err_out;
 100         }
 101
 102         return keys_ex;
 103
 104 err_out:
 105         kfree(keys_ex);
 106         return ERR_PTR(err);
 107 }
 108
 109 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 110                                  struct tcf_pedit_key_ex *keys_ex, int n)
 111 {
 112         struct nlattr *keys_start = nla_nest_start_noflag(skb,
 113                                                           TCA_PEDIT_KEYS_EX);
 114
 115         if (!keys_start)
 116                 goto nla_failure;
 117         for (; n > 0; n--) {
 118                 struct nlattr *key_start;
 119
 120                 key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
 121                 if (!key_start)
 122                         goto nla_failure;
 123
 124                 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 125                     nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
 126                         goto nla_failure;
 127
 128                 nla_nest_end(skb, key_start);
 129
 130                 keys_ex++;
 131         }
 132
 133         nla_nest_end(skb, keys_start);
 134
 135         return 0;
 136 nla_failure:
 137         nla_nest_cancel(skb, keys_start);
 138         return -EINVAL;
 139 }
 140
 141 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 142                           struct nlattr *est, struct tc_action **a,
 143                           int ovr, int bind, bool rtnl_held,
 144                           struct tcf_proto *tp, struct netlink_ext_ack *extack)
 145 {
 146         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 147         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 148         struct tcf_chain *goto_ch = NULL;
 149         struct tc_pedit_key *keys = NULL;
 150         struct tcf_pedit_key_ex *keys_ex;
 151         struct tc_pedit *parm;
 152         struct nlattr *pattr;
 153         struct tcf_pedit *p;
 154         int ret = 0, err;
 155         int ksize;
 156
 157         if (!nla) {
 158                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 159                 return -EINVAL;
 160         }
 161
 162         err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 163                                           pedit_policy, NULL);
 164         if (err < 0)
 165                 return err;
 166
 167         pattr = tb[TCA_PEDIT_PARMS];
 168         if (!pattr)
 169                 pattr = tb[TCA_PEDIT_PARMS_EX];
 170         if (!pattr) {
 171                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 172                 return -EINVAL;
 173         }
 174
 175         parm = nla_data(pattr);
 176         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 177         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 178                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 179                 return -EINVAL;
 180         }
 181
 182         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 183         if (IS_ERR(keys_ex))
 184                 return PTR_ERR(keys_ex);
 185
 186         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 187         if (!err) {
 188                 if (!parm->nkeys) {
 189                         tcf_idr_cleanup(tn, parm->index);
 190                         NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 191                         ret = -EINVAL;
 192                         goto out_free;
 193                 }
 194                 ret = tcf_idr_create(tn, parm->index, est, a,
 195                                      &act_pedit_ops, bind, false);
 196                 if (ret) {
 197                         tcf_idr_cleanup(tn, parm->index);
 198                         goto out_free;
 199                 }
 200                 ret = ACT_P_CREATED;
 201         } else if (err > 0) {
 202                 if (bind)
 203                         goto out_free;
 204                 if (!ovr) {
 205                         ret = -EEXIST;
 206                         goto out_release;
 207                 }
 208         } else {
 209                 ret = err;
 210                 goto out_free;
 211         }
 212
 213         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 214         if (err < 0) {
 215                 ret = err;
 216                 goto out_release;
 217         }
 218         p = to_pedit(*a);
 219         spin_lock_bh(&p->tcf_lock);
 220
 221         if (ret == ACT_P_CREATED ||
 222             (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 223                 keys = kmalloc(ksize, GFP_ATOMIC);
 224                 if (!keys) {
 225                         spin_unlock_bh(&p->tcf_lock);
 226                         ret = -ENOMEM;
 227                         goto put_chain;
 228                 }
 229                 kfree(p->tcfp_keys);
 230                 p->tcfp_keys = keys;
 231                 p->tcfp_nkeys = parm->nkeys;
 232         }
 233         memcpy(p->tcfp_keys, parm->keys, ksize);
 234
 235         p->tcfp_flags = parm->flags;
 236         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 237
 238         kfree(p->tcfp_keys_ex);
 239         p->tcfp_keys_ex = keys_ex;
 240
 241         spin_unlock_bh(&p->tcf_lock);
 242         if (goto_ch)
 243                 tcf_chain_put_by_act(goto_ch);
 244         if (ret == ACT_P_CREATED)
 245                 tcf_idr_insert(tn, *a);
 246         return ret;
 247
 248 put_chain:
 249         if (goto_ch)
 250                 tcf_chain_put_by_act(goto_ch);
 251 out_release:
 252         tcf_idr_release(*a, bind);
 253 out_free:
 254         kfree(keys_ex);
 255         return ret;
 256
 257 }
 258
 259 static void tcf_pedit_cleanup(struct tc_action *a)
 260 {
 261         struct tcf_pedit *p = to_pedit(a);
 262         struct tc_pedit_key *keys = p->tcfp_keys;
 263
 264         kfree(keys);
 265         kfree(p->tcfp_keys_ex);
 266 }
 267
 268 static bool offset_valid(struct sk_buff *skb, int offset)
 269 {
 270         if (offset > 0 && offset > skb->len)
 271                 return false;
 272
 273         if  (offset < 0 && -offset > skb_headroom(skb))
 274                 return false;
 275
 276         return true;
 277 }
 278
 279 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 280                                 enum pedit_header_type htype, int *hoffset)
 281 {
 282         int ret = -EINVAL;
 283
 284         switch (htype) {
 285         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 286                 if (skb_mac_header_was_set(skb)) {
 287                         *hoffset = skb_mac_offset(skb);
 288                         ret = 0;
 289                 }
 290                 break;
 291         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 292         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 293         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 294                 *hoffset = skb_network_offset(skb);
 295                 ret = 0;
 296                 break;
 297         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 298         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 299                 if (skb_transport_header_was_set(skb)) {
 300                         *hoffset = skb_transport_offset(skb);
 301                         ret = 0;
 302                 }
 303                 break;
 304         default:
 305                 ret = -EINVAL;
 306                 break;
 307         }
 308
 309         return ret;
 310 }
 311
 312 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 313                          struct tcf_result *res)
 314 {
 315         struct tcf_pedit *p = to_pedit(a);
 316         int i;
 317
 318         if (skb_unclone(skb, GFP_ATOMIC))
 319                 return p->tcf_action;
 320
 321         spin_lock(&p->tcf_lock);
 322
 323         tcf_lastuse_update(&p->tcf_tm);
 324
 325         if (p->tcfp_nkeys > 0) {
 326                 struct tc_pedit_key *tkey = p->tcfp_keys;
 327                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 328                 enum pedit_header_type htype =
 329                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 330                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 331
 332                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 333                         u32 *ptr, hdata;
 334                         int offset = tkey->off;
 335                         int hoffset;
 336                         u32 val;
 337                         int rc;
 338
 339                         if (tkey_ex) {
 340                                 htype = tkey_ex->htype;
 341                                 cmd = tkey_ex->cmd;
 342
 343                                 tkey_ex++;
 344                         }
 345
 346                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 347                         if (rc) {
 348                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 349                                         htype);
 350                                 goto bad;
 351                         }
 352
 353                         if (tkey->offmask) {
 354                                 u8 *d, _d;
 355
 356                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 357                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 358                                                 hoffset + tkey->at);
 359                                         goto bad;
 360                                 }
 361                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 362                                                        sizeof(_d), &_d);
 363                                 if (!d)
 364                                         goto bad;
 365                                 offset += (*d & tkey->offmask) >> tkey->shift;
 366                         }
 367
 368                         if (offset % 4) {
 369                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 370                                 goto bad;
 371                         }
 372
 373                         if (!offset_valid(skb, hoffset + offset)) {
 374                                 pr_info("tc action pedit offset %d out of bounds\n",
 375                                         hoffset + offset);
 376                                 goto bad;
 377                         }
 378
 379                         ptr = skb_header_pointer(skb, hoffset + offset,
 380                                                  sizeof(hdata), &hdata);
 381                         if (!ptr)
 382                                 goto bad;
 383                         /* just do it, baby */
 384                         switch (cmd) {
 385                         case TCA_PEDIT_KEY_EX_CMD_SET:
 386                                 val = tkey->val;
 387                                 break;
 388                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 389                                 val = (*ptr + tkey->val) & ~tkey->mask;
 390                                 break;
 391                         default:
 392                                 pr_info("tc action pedit bad command (%d)\n",
 393                                         cmd);
 394                                 goto bad;
 395                         }
 396
 397                         *ptr = ((*ptr & tkey->mask) ^ val);
 398                         if (ptr == &hdata)
 399                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 400                 }
 401
 402                 goto done;
 403         } else {
 404                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 405         }
 406
 407 bad:
 408         p->tcf_qstats.overlimits++;
 409 done:
 410         bstats_update(&p->tcf_bstats, skb);
 411         spin_unlock(&p->tcf_lock);
 412         return p->tcf_action;
 413 }
 414
 415 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 416                           int bind, int ref)
 417 {
 418         unsigned char *b = skb_tail_pointer(skb);
 419         struct tcf_pedit *p = to_pedit(a);
 420         struct tc_pedit *opt;
 421         struct tcf_t t;
 422         int s;
 423
 424         s = struct_size(opt, keys, p->tcfp_nkeys);
 425
 426         /* netlink spinlocks held above us - must use ATOMIC */
 427         opt = kzalloc(s, GFP_ATOMIC);
 428         if (unlikely(!opt))
 429                 return -ENOBUFS;
 430
 431         spin_lock_bh(&p->tcf_lock);
 432         memcpy(opt->keys, p->tcfp_keys,
 433                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 434         opt->index = p->tcf_index;
 435         opt->nkeys = p->tcfp_nkeys;
 436         opt->flags = p->tcfp_flags;
 437         opt->action = p->tcf_action;
 438         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 439         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 440
 441         if (p->tcfp_keys_ex) {
 442                 if (tcf_pedit_key_ex_dump(skb,
 443                                           p->tcfp_keys_ex,
 444                                           p->tcfp_nkeys))
 445                         goto nla_put_failure;
 446
 447                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 448                         goto nla_put_failure;
 449         } else {
 450                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 451                         goto nla_put_failure;
 452         }
 453
 454         tcf_tm_dump(&t, &p->tcf_tm);
 455         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 456                 goto nla_put_failure;
 457         spin_unlock_bh(&p->tcf_lock);
 458
 459         kfree(opt);
 460         return skb->len;
 461
 462 nla_put_failure:
 463         spin_unlock_bh(&p->tcf_lock);
 464         nlmsg_trim(skb, b);
 465         kfree(opt);
 466         return -1;
 467 }
 468
 469 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 470                             struct netlink_callback *cb, int type,
 471                             const struct tc_action_ops *ops,
 472                             struct netlink_ext_ack *extack)
 473 {
 474         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 475
 476         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 477 }
 478
 479 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 480 {
 481         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 482
 483         return tcf_idr_search(tn, a, index);
 484 }
 485
 486 static struct tc_action_ops act_pedit_ops = {
 487         .kind           =       "pedit",
 488         .id             =       TCA_ID_PEDIT,
 489         .owner          =       THIS_MODULE,
 490         .act            =       tcf_pedit_act,
 491         .dump           =       tcf_pedit_dump,
 492         .cleanup        =       tcf_pedit_cleanup,
 493         .init           =       tcf_pedit_init,
 494         .walk           =       tcf_pedit_walker,
 495         .lookup         =       tcf_pedit_search,
 496         .size           =       sizeof(struct tcf_pedit),
 497 };
 498
 499 static __net_init int pedit_init_net(struct net *net)
 500 {
 501         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 502
 503         return tc_action_net_init(tn, &act_pedit_ops);
 504 }
 505
 506 static void __net_exit pedit_exit_net(struct list_head *net_list)
 507 {
 508         tc_action_net_exit(net_list, pedit_net_id);
 509 }
 510
 511 static struct pernet_operations pedit_net_ops = {
 512         .init = pedit_init_net,
 513         .exit_batch = pedit_exit_net,
 514         .id   = &pedit_net_id,
 515         .size = sizeof(struct tc_action_net),
 516 };
 517
 518 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 519 MODULE_DESCRIPTION("Generic Packet Editor actions");
 520 MODULE_LICENSE("GPL");
 521
 522 static int __init pedit_init_module(void)
 523 {
 524         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 525 }
 526
 527 static void __exit pedit_cleanup_module(void)
 528 {
 529         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 530 }
 531
 532 module_init(pedit_init_module);
 533 module_exit(pedit_cleanup_module);